1. Field of the Invention
The present invention relates to a noncontact stirring method, a noncontact stirring apparatus, a method and apparatus for reacting nucleic acid hybridization using the apparatus, a method for detecting nucleic acid in a sample, an apparatus for detecting nucleic acid, a method for detecting antibodies in a sample (ELISA reaction), and an apparatus for detecting antibodies (ELISA reaction apparatus) in droplets of 1 mL or less in a high-voltage alternating-current electric field, particularly minute microliter-order droplets that can be utilized to speed up biodetection processes and hybridization processes in genetic analysis, ELISA (Enzyme-Linked ImmunoSorbent Assay: used to detect and quantify the concentration of antibodies or antigens in a sample) antigen fixing processes, blocking processes, antibody-antigen reaction processes and color reaction processes, in pathogen identification, CRP tests (C-Reactive Protein: examining for the presence or absence of protein in looking for inflammation, infection or tissue damage), and methods of propagating cells or bacilli such as colon bacilli in a liquid culture medium.
2. Description of the Prior Art
In genetic analysis, ELISA antigen fixing processes, blocking processes, antigen-antibody reaction processes and color reaction processes, pathogen identification, CRP tests, biodetection and other such chemical analysis processes, having the reactions take place while the sample solution is stirred takes a lot of time, so there is a need to speed this up for the future of tailor-made medicine.
Industrially, analysis and quantification of various biological components such as cells, sugar, protein and nucleic acid are conducted on a routine basis in a wide range of tests, such as clinical tests, food tests and environmental tests. In the field of clinical tests in particular, the diagnosis of diseases, the determining of the efficacy of treatments, and the measurement of antibodies are done by analyzing and quantifying specific biological components in bodily fluids such as blood, urine and the like. Utilizing the interaction of DNA (deoxyribonucleic acid) and intercalators, antigen fixing reactions based on hydrophobic bonding, antigen-antibody reactions, and electrophoresis utilizing the physicochemical properties of the target substance are methods in general use for analyzing and quantifying biological components. However, depending on what the target biological component is, the reactions and operation of these methods may take up much time and lack precision, and in terms of principle are limited and may not provide accurate analysis.
For example, in the case of a nucleic acid hybridization process in genetic analysis that uses static reactions, the reaction time is long, in the order of 60 minutes to 6 hours. If a shaker is to be used for stirring, the liquid amount must be at least 1 mL, and a specific time is required for the solution to reach the optimum temperature, making it difficult to speed up the process. Attempts have been made to reduce the time taken to reach the optimum temperature by reducing the liquid amount of the solution to 1 mL or less, and in particular to a minute amount in the microliter-order, in addition to which the minute amount of solution is vigorously stirred internally, to thereby improve the speed of the hybridization reaction.
Because in a nucleic acid hybridization reaction it is considered that the types of molecules that form pairs are chain molecules, the reaction cannot be completed by a single collision, the formation of a continuous chain pairing reaction proceeding through a plurality of molecular collisions. That is, the reaction time can be greatly reduced by using stirring for mutual collision.
For example, in an immune reaction in an ELISA, at each step generally a liquid amount of 50 μL to 100 μL has to be left static for 30 minutes to 1 hour, so the whole process requires around 4 hours. The reaction proceeds by molecular diffusion. Therefore, it is possible to greatly reduce the reaction time by reducing the amount of the solution and by stirring it.
As described in the above, in order to improve reaction speed using a solution amount of 1 mL or less, and in particular a minute microliter-order amount, to expedite obtaining a high-quality outcome, there is a need for a noncontact stirring technology that does not use rotors or stirring elements.
As noncontact stirring technology that has already been proposed, there are known commercial shakers that impart shaking (undulating motion) to a solution, a method that blows air bubbles onto the surface of the solution, a method that imparts ultrasonic waves, and so forth.